Device and Method for Unfolding Packaging Carton Sleeves

ABSTRACT

A device for unfolding packaging carton sleeves having a mechanism for providing the flat carton sleeves, a transfer unit, which can be rotated about a rotational axis, having at least one suction member for adhering to the carton sleeves and for transferring the carton sleeves to a conveyor belt, wherein the suction member is at a distance from the rotational axis. The conveyor belt includes at least one pocket for receiving the carton sleeves. The distance between the suction member and the rotational axis is constant and consequently the carton sleeves are channelled along a circular track.

The invention relates to a device for unfolding packaging carton sleeves having a mechanism for providing the flat carton sleeves, a transfer unit, which can be rotated about a rotational axis and which has at least one suction member for adhering to the carton sleeves by suction, wherein the suction member is at a distance from the rotational axis, and a conveyor belt with at least one pocket for receiving the carton sleeves.

The invention also relates to a method for unfolding packaging carton sleeves comprising the following steps: provision of the carton sleeves by a mechanism, adhesion to the carton sleeves by suction and advancement of said carton sleeves by a transfer unit rotating about a rotational axis having at least one suction member, and unfolding of the carton sleeves by inserting said carton sleeves into a pocket attached to a conveyor belt.

Numerous devices and methods are known in the field of packaging technology that can be used to unfold flat carton sleeves so that said sleeves can then be filled with their respective contents. Complex unfolding devices are often required here, which pull the flat carton sleeves apart from both sides in order to bring them into their unfolded form.

An unfolding device of this type is known from EP 0 112 605 A2. Suction members adhere to the flat carton sleeves by suction from both sides. The opposing suction members are then moved apart from each other and consequently the opposing sides of the carton sleeve are pulled apart and the carton sleeve is unfolded. The solution described in EP 0 112 605 A2 has the disadvantage that the design of the unfolding machine is highly complex since suction members are intended to adhere to the carton sleeve by suction from both sides, which suction members can be moved towards and away from each other.

A further option for unfolding flat carton sleeves is known from WO 96/23655 A1. In this folding device, the carton sleeves are delivered into pockets on a conveyor in a flat state. A rotatable arm with a suction member is attached to each pocket, which is intended to unfold the carton sleeve from the flat state into the tubular state. This unfolding device also has the disadvantage of a complex design, since a rotatable arm with a suction element has to be provided at each pocket.

Separate unfolding devices can be dispensed with, however, if a relative speed, which occurs, for example, when transferring carton sleeves from a first station to a second station of a filling line, is used to unfold the carton sleeves. In other words, the carton sleeve ‘abuts’ a component part of the second station in the line whilst said sleeve is still being fed from the first station in the line, which conveys the sleeve further, and is folded in this manner.

A device and method of this type for folding, filling and sealing cartons is known from U.S. Pat. No. 3,060,654. The carton sleeves are unfolded by a rotating unit, which withdraws the flat cartons from a magazine and transfers them to a conveyor belt. This step is illustrated in particular in FIGS. 15a to 15f . The carton sleeves are unfolded upon transfer from the rotating unit to the conveyor belt and clamped between a pair of L-shaped lugs which are attached to the conveyor belt. One leg of the L-shaped lug is attached to the conveyor belt; the other leg extends beyond the conveyor belt and is intended to restrain the carton at the side. A hook is provided at one end of the protruding leg, which is intended to hold the carton sleeve in its position between both lugs. The rotating unit has arms with suction heads, which, in addition to a rotational movement, also perform a radial movement in the direction of the conveyor belt in order to transfer the carton sleeves to the conveyor belt. Insertion of the carton sleeves between both L-shaped lugs is made possible by inserting the carton sleeves at a point where the conveyor belt runs in a curved line and consequently the protruding legs of the L-shaped lug do not run parallel, but are spread apart. The conveyor belt travels in a straight line again after the carton sleeves have been inserted, wherein the spread protruding legs of the lugs return to their usual position and the carton sleeve is clamped between the protruding legs of the lugs that now run parallel.

The solution disclosed in U.S. Pat. No. 3,060,654 firstly has the disadvantage that it is extremely complex in terms of design. The reason for this is that the arms of the rotating mechanism are intended to perform not only a rotational movement, but also a movement in a radial direction in order to draw the carton sleeves from the magazine and channel them towards the conveyor belt. A further disadvantage is the lack of variability of the configuration. Since the carton sleeves are intended to be clamped between a pair of L-shaped lugs in the manner described above, the carton sleeves have to be inserted into the lugs at a point where the conveyor belt moves from a curved course to a straight course. Provision is not made, however, for inserting and fixing the carton sleeves upstream or downstream of this transitional region.

The invention is therefore based on the problem of refining and developing the device referred to at the start and presented in detail above, as well as the method also referred to at the start and presented in detail above, such that reliable unfolding and transfer of the carton sleeves to the conveyor belt is possible even with a simple design and a simple procedure.

This problem is solved in a device according to the preamble of claim 1 in that the distance between the suction member and the rotational axis is constant and consequently the carton sleeves are channelled along a circular track.

One aspect of the present invention is that suction members and thus also the carton sleeves to which the suction members adhere by suction are guided or channelled along a circular track. As a result of this geometrically simple guiding of the suction members and the carton sleeves, the transfer unit can be designed in a particularly uncomplicated and cost-effective way. For example, the transfer unit may have a cylindrical drum as the main component. More particularly, it is not necessary to mount the suction members so that they are moveable in a radial direction. This facilitates the mounting and/or attachment of the suction members to the transfer unit considerably. Supplying the suction members with negative pressure is also facilitated as a result of the unchanging position of the suction members. Finally, the transfer unit in a device according to the invention is characterised by particularly strong robustness since moving parts can largely be dispensed with. The omission of moving parts also has advantages in terms of (food) hygiene since the lubrication of said parts is not applicable.

Provision is made according to one embodiment of the invention that the conveyor belt runs in a straight line in the region of the device. Insertion of the carton sleeves into the pockets attached to the conveyor belt is facilitated by the conveyor belt running in a straight line as the pockets are located sufficiently close to the transfer unit for a longer section than when the belt runs in a curved line. In addition, there are no centrifugal forces when the belt runs in a straight line which is particularly advantageous at high operating speeds. However, when the conveyor belt leaves the region of the device, it is no longer necessary for the conveyor belt to run in a straight line; the conveyor belt can also be diverted in this region. Alternatively, provision can be made for the conveyor belt to run in a curved direction in the region of the device. More particularly, the conveyor belt may run along a circular track in the region of the device. The arrangement of the device in a curved or circular section of the conveyor belt has the advantage that those regions into which the conveyor belt is diverted can also be used. This makes a particularly compact design of a system for unfolding, filling and sealing carton sleeves possible.

A further design of the invention makes provision that the mechanism has at least one movably mounted finger with a lug for separating the flat carton sleeves. The height of said lug preferably corresponds to the height of a flat folded carton. The finger can be moved forwards and backwards. This linear movement in a longitudinal direction can be intersected by a movement in a transverse direction and consequently overall, the finger moves along an approximately oval trajectory. This design means that that the finger engages with precisely one carton sleeve in each movement cycle with the lug and pushes said carton sleeve away from the stack. The finger can have a precisely defined travel and consequently the carton sleeve removed from the stack can be advanced into a desired position where it can be adhered by suction by the suction members. The place where the suction members engage with the carton sleeves can be changed by varying the travel. For example, the travel can be in the region of between 1 cm and 4 cm, more particularly between 2 cm and 3 cm.

Provision is made according to a further teaching of the invention that the mechanism has a hopper for channelling the carton sleeves, the central plane of which has an offset in relation to the rotational axis of the transfer unit. The length of the offset may be in the region of between 1 cm and 6 cm, for example, more particularly between 2 cm and 4 cm. The offset means that the suction members do not adhere to the carton sleeves by suction centrally, but on their edge regions. This facilitates the insertion of the carton sleeves into the pockets since the carton sleeves protrude particularly far from the suction members when they are adhered by suction on the edge regions thereof.

Provision is made in a further embodiment of the invention that all suction members are arranged at the same distance from the rotational axis of the transfer unit. The transfer unit may have more than one suction member. If several suction members are present on the transfer unit, it is advantageous to arrange all suction members at the same radial distance from the rotational axis of the transfer unit in order to be able to adhere to the carton sleeves by suction reliably. The suction members may be arranged in a row such that each carton sleeve is adhered to by suction by a plurality of suction members at the same time. A plurality of rows of suction members may also be provided on the transfer unit. In this manner, a plurality of carton sleeves can be adhered to by suction and unfolded with each rotation of the transfer unit. In a preferred embodiment, the rows of suction members are uniformly arranged over the area of the transfer unit at identical distances from each other.

Provision is made according to a further embodiment of the invention that the suction members are inclined at an angle to a tangential plane touching the circular track. The angle may be in the region of between 1° and 10°, for example, more particularly between 3° and 6°. Preferably the suction members are inclined towards the rotational direction of the transfer unit. This inclination has the advantage that the suction members do not remain hanging on the carton sleeves stored in the magazine. This risk exists due to the fact that the circumferential edges of non-inclined suction members lie in a tangential plane and consequently the foremost and very back point of a non-inclined suction member seen in the direction of rotation are spaced at a greater radial distance from the rotational axis than the centre of the suction members, which lies precisely on the circular track along which the suction members are guided. It can be achieved in particular by inclining the suction members that the foremost point of the suction element seen from the direction rotation again lies within the circular track along which the suction members are guided. The secondary effects of reducing the risk of collision, the suction members can be attached to the carton sleeves better as a result of the inclination. Alternatively, or in addition to the inclination of the suction members, the magazine which contains the carton sleeves may also be inclined at an appropriate angle.

Provision is made in a further embodiment of the invention that the pockets have two rigid side walls. A rigid back wall can also be provided. A rigid wall is understood as being a wall, which is resistant to bending and more particularly, cannot be tilted or folded down. Rigid side walls offer a better stop point for the carton sleeves than flexible or expandable side walls, which facilitates the unfolding of the carton sleeves. A rigid back wall provides a good attachment option for the side walls.

It is further suggested in relation to said embodiments that the side walls of the pockets protrude vertically from the back wall and/or the conveyor belt. The unfolding of the carton sleeves is supported by the vertical line of the side walls as the carton sleeves are also intended to be at a 90° angle in the unfolded state.

A further teaching of the invention makes the provision that the pockets have at least one spring member for clamping the carton sleeve in a pocket. The flexible spring member allows particularly reliable securing of the carton sleeve inside the pocket. The spring member can be pushed back by the carton sleeve or bent to the side in order to insert a carton sleeve into the pockets. Particularly in the case of rigid pockets, the spring member ensures the secure retention of the carton sleeves as rigid pockets themselves do not have a strong clamping effect. In rigid pockets without a spring member, the clamping effect therefore has to be applied solely through the elasticity of the carton sleeve which has proven less reliable than the use of spring members, especially at high operating speeds.

It is further suggested in relation to this teaching that the end of the spring member is configured in the shape of a hook. The hook shape enables particularly good engagement behind the carton sleeves and reliable retention inside the pocket.

Provision is made in a further embodiment of the invention that the minimum distance between the circular track of the suction members and the back wall of the pocket is shorter than the length of the side walls of the pockets. This arrangement means that the suction members are directed very close to the side walls of a pocket and even ‘dip into’ a pocket in the region between both side walls. This ensures complete unfolding of the carton sleeves as said sleeves are pressed deep into the pockets and the forces required for unfolding are introduced to the carton sleeves solely by the suction members and the pocket. The depth to which the suction members ‘dip into’ the pockets may be in the region of between 1 mm and 10 mm depending on the carton sleeve format.

The problem described above is solved in a method according to the preamble of claim 14 in that the transfer unit channels the carton sleeves along a circular track at a constant distance between the suction members and the rotational axis.

As has already been explained in connection with the device according to the invention, guiding or channeling the carton sleeves along a circular track has the advantage of being a particularly simple procedure. More particularly there is no need for the carton sleeves to be moved in a radial direction.

It is suggested according to an embodiment of the method that the transfer unit rotates at an angular velocity that is always greater than zero. The transfer unit should therefore not be stopped at any time as would be the case in intermittent operation. The angular velocity may fluctuate around an average value, for example, wherein the characteristics of the angular velocity are repeated in the same manner for each carton sleeve. A cyclical variation of the angular velocity enables optimisation of the insertion of the carton sleeves into the pockets. The transfer unit can also rotate at a constant angular velocity. A constant angular velocity has the advantage of a particularly efficient process. More particularly, no additional energy needs to be used to speed up and slow down the transfer unit. A constant angular velocity also has a positive effect on the useful life of the machine, whereas operation at variable angular velocity or even intermittent operation generally shortens useful life.

Provision is made in a further embodiment of the method that the conveyor belt moves at a speed which is always greater than zero. As has already been stated in respect of the angular velocity of the transfer unit, the conveyor belt should not be stopped at any time either. However, a cyclical variation of the speed, for example a fluctuation around an average value, is possible. In order to ensure synchronisation between transfer unit and conveyor belt, the characteristics of the speed must also be repeated here in the same manner for each carton sleeve. The conveyor belt can also move at a constant speed. Both the amount and the direction of speed of the conveyor belt may be constant. Preferably, the speed of the conveyor belt corresponds more or less to the track speed at which the suction members are guided along the circular track. In the event of a cyclical variation of the angular velocity of the transfer unit and the speed of the conveyor belt, said equivalence should, however, be observed for the average speeds and more particularly for speeds at the point of transfer of the carton sleeves. In this manner a synchronous run can be achieved between transfer unit and conveyor belt and it can be ensured that the carton sleeves to which the suction members adhere by suction and the pockets assigned to said sleeves are brought together at precisely the same time. The unfolding of the carton sleeves is successful nevertheless since the front edge of the carton sleeve is at a greater radial distance from the rotational axis of the transfer unit than the suction members and therefore also has a higher track speed than the suction members and the pockets.

It is suggested in a further embodiment of the method that the carton sleeves are separated in the mechanism by a movably mounted finger, which has a travel in the range of between 1 cm and 4 cm. The travel in the direction of a carton sleeve corresponds to the distance which an unstacked carton sleeve is advanced. The engagement position of the suction members in relation to the carton sleeves can be changed by varying the travel.

It is suggested according to one development of the method that the suction members establish a negative pressure in an angular range of 350°<φ<10°. Provision can be made in particular that the suction members build up negative pressure in an angular range of approx. φ=0°. The angle of rotation φ starts at 0° in the region of the magazine and increases during the course of rotation of the transfer unit. Negative pressure can therefore be built up to 10° prior to reaching the magazine. In the region of the minimal distance between suction members and conveyor belt, the angle of rotation is preferably approx. 180°. Depending on the arrangement of magazine and conveyor belt, the angle of rotation in the region of the conveyor belt may have other values and for example, be in the region of between φ=120° and φ=270°. Negative pressure should preferably be established shortly before reaching the magazine by extracting air by suction.

Provision is made in a further embodiment of the method that the suction members dissipate the negative pressure in an angular range of 125°<φ<145°. Provision can be made in particular that the suction members dissipate the negative pressure again in an angular range of approx. φ=135°. The negative pressure should be dissipated in order to release the carton sleeve. This occurs, for example, by ending the suction process. The negative pressure should be dissipated after the carton sleeve has contact with the pocket, however, before the suction members have reached their minimum distance from the conveyor belt. In an arrangement of the conveyor belt in the region of φ=180°, the negative pressure should therefore be dissipated again in the region of between 125° (i.e. 55° prior to reaching the minimum distance from the conveyor belt) and 145° (i.e. 35° prior to reaching the minimum distance from the conveyor belt). In an arrangement of the conveyor belt, which differs from the 180° position, a different rotational angular range is produced in a corresponding manner for dissipating the negative pressure.

Finally, it is suggested that the suction members adhere to the carton sleeves by suction at a distance from their centre, which is in the range between 0 cm and 6 cm, in particular between 1 cm and 3 cm. The distance to the centre may be between 10% and 40% of the width of the carton sleeves. As a result of the eccentric adhesion to the carton sleeves by suction, the front edge of the carton sleeve is clearly further away from the suction members than the back edge. This facilitates a sufficiently deep insertion of the carton sleeves into the pockets.

The invention is explained in more detail below using a drawing which shows only one preferred embodiment. In the drawing:

FIG. 1A shows a blank for folding a carton sleeve known from the prior art,

FIG. 1B shows a carton sleeve in a flat folded state known from the prior art, which is formed from the blank shown in FIG. 1A,

FIG. 1C shows the carton sleeve from FIG. 1B in an unfolded state,

FIG. 2 shows a top view of a device according to the invention for unfolding carton sleeves, and

FIG. 3 shows a system known from the prior art for filling packagings with foodstuffs.

FIG. 1A shows a blank 1 known from the prior art from which a carton sleeve can be formed. The blank 1 may comprise several layers of different materials, for example, paper, cardboard, plastic or metal, more particularly aluminium. The blank 1 has a plurality of folding lines 2 which are intended to facilitate the folding of blank 1 and divide the blank 1 into several panels. The blank 1 can be divided into a first side panel 3, a second side panel 4, a front panel 5, a rear panel 6, a sealing panel 7, four base panels 8 and four gable panels 9. A carton sleeve can be formed from the blank 1 by folding the blank 1 such that the sealing panel 7 can be attached to the front panel 5, more particularly fused.

FIG. 1B shows a carton sleeve 10 in a flat folded state known from the prior art. The features already described in connection with FIG. 1A are provided with corresponding reference signs in FIG. 1B. The carton sleeve 10 is formed from the blank 1 shown in FIG. 1A. The blank 1 has been folded for this purpose such that the sealing panel 7 and the front panel 5 are overlapping and consequently both panels can be fused together flat. This results in a longitudinal seam 11. The carton sleeve 10 is shown in a flat folded state in FIG. 1B. In said state, a side panel 4 (hidden in FIG. 1B) lies underneath the front panel 5 whereas the other side panel 3 lies on top of the rear panel 6 (hidden in FIG. 1B). A plurality of carton sleeves 10 can be stacked in the flat folded state in a particularly space saving manner. The carton sleeves 10 are therefore often stacked at the place where they are produced and transported stack by stack to the place where they are filled. The carton sleeves are not unstacked and unfolded in order to be filled with content, for example foodstuffs, until they arrive here.

FIG. 1C shows the carton sleeve 10 from FIG. 1B in an unfolded state. Here, the features already described in connection with FIG. 1A or FIG. 1B are provided with corresponding reference signs. The unfolded state is understood as a configuration where an angle of approx. 90° is formed between both respectively adjacent panels 3, 4, 5, 6, and consequently the carton sleeve 10 has a square or rectangular cross-section depending on the shape of said panels. Accordingly, the opposite side panels, 3, 4, are arranged parallel to each other. The same applies to the front panel 5 and the rear panel 6.

The carton sleeve 10 used may have different dimensions (‘formats’). The width of the side panels 3, 4 may be in the region of between 30 mm and 80 mm. The width of the front panel 5 and the rear panel 6 may be in the region of between 40 mm and 120 mm. Flat folded carton sleeves 10 therefore have a width in the region of between 70 mm (30 mm+40 mm) and 200 mm (80 mm+120 mm). Finally, the height of the side panels 3, 4 and the front and rear panels 5, 6 may be in the region of between 50 mm and 250 mm. For example, a filled and sealed carton sleeve with a filling volume of 80 ml will have external dimensions of 47 mm×32.5 mm 55 mm. Accordingly, a carton with a filling volume of 2000 ml will have external dimensions of 114 mm×74 mm×245 mm.

FIG. 2 shows a top view of a device 12 according to the invention for unfolding carton sleeves 10. The device 12 comprises a mechanism 13 for providing, in particular for separating flat carton sleeves 10, a transfer unit 14 and a conveyor belt 15.

The mechanism 13, which is also described as ‘magazine’, has a housing 16 with a hopper 17, into which a stack of flat carton sleeves 10 can be placed. The hopper 17 has a central plane 18, which runs centrally through the carton sleeves 10 placed into said hopper 17. As shown in FIG. 2, the central plane 18 may be aligned vertically in relation to the conveyor belt 15. Alternatively, the central plane 18 may also be inclined in relation to said vertical. The mechanism 13 also has a plurality of fingers 19 arranged in a row one behind the other, each of which has a lug 20. The height of the lug 20 more or less corresponds to the height of a flat folded carton sleeve 10. The fingers 19 perform a cyclical movement to unstack the carton sleeves 10, the travel 21 of which movement is shown by an arrow in FIG. 2. The backwards and forwards movement of the fingers 19 cause the fingers 19 to push with their lugs 20 a carton sleeve 10 out of the mechanism 13 in each movement cycle through an opening 22 from where said carton sleeves can be transferred to the transfer unit 14. The remaining carton sleeves 10 are fed constantly by a force F directed towards the fingers 19 and consequently continuous unstacking and separation of the carton sleeves 10 is ensured.

The transfer unit 14 comprises a drum 23 onto which a plurality of suction members 24 are attached. The drum 23 shown in FIG. 2 and preferred in this respect has a cylindrical shape and thus a circular cross-sectional area. The four rows of suction members 24 are arranged on a circular track 25 at a constant distance 26 or radius respectively, wherein the circular track 25 runs through the central points of the suction members 24. The suction members 24 are fixed in position and consequently all suction members 24 are always at the same, constant distance from a rotational axis 27 about which the drum 23 rotates at an angular velocity w and an angle of rotation cp. The mechanism 13 and the transfer unit 14 are arranged such that an offset 28 is created between the rotational axis 27 of the transfer unit 14 and the central plane 18 of the mechanism 13. The travel 21 of the fingers 19 and the offset 28 causes the suction members 24 not to adhere to the carton sleeves 10 by suction centrally, but on the edges thereof.

The suction members 24 may be charged with negative pressure via cables (not shown in FIG. 2) in order to adhere to the carton sleeves 10 by suction in the region of the mechanism 13 (at an approx. angle of rotation of φ=0°) and during the further rotation of the drum 23 transfer said carton sleeves to the conveyor belt 15 (at an approx. angle of rotation of φ=180°). The suction members 24 are preferably slightly inclined and consequently the edges of the suction members 24 lie on a plane 29, which is inclined at an angle a in relation to the tangential plane 30 of the circular track 25. In this manner the suction members 24 are inclined slightly towards the direction of rotation of the drum 23 and are in a better position to adhere to the carton sleeves 10 by suction.

The conveyor belt 15 runs in a straight line in the section shown in FIG. 2 and has a speed v. The conveyor belt 15 may be a belt or a chain. Several pockets 31 are attached to the conveyor belt 15 which serve to receive the carton sleeves 10. The pockets 31 comprise a back wall 32 and two side walls 33. The back wall 32 runs parallel to the conveyor belt 15 and is connected thereto. Both side walls 33 protrude vertically from the back wall 32; they are therefore arranged parallel to one another. The rear wall 32 and both side walls 33 are made of metal and have no hinges or similar and consequently a rigid pocket 31 is involved here. The pockets 31 have two spring members 34, wherein a spring member 34 is arranged preferably on each side wall 33. The spring members 34 are made of an elastic material, for example spring steel or flexible plastic, and have a protruding end 35 which is configured in the shape of a hook. The hook shape allows the spring members 34 to retain or firmly clamp the carton sleeves 10 in place in the pockets 31.

The pockets 31 are arranged at a constant distance from each other, which is also described as ‘pass’. Said distance 36 corresponds approximately to the length of an arc segment which runs along the circular track 25 between two adjacent suction members; in the case of four suction members 24, the distance 36 corresponds to approx. one quarter of the circumference of the circular track 25. The transfer unit 14 is arranged opposite the conveyor belt 15 such that there is a minimum distance 37 between the circular track 25 of the suction members 24 and the back wall 32 of the pockets 31, which is slightly shorter than the length of the side walls 33 of the pockets 31, and consequently the suction members 24 ‘dip into’ the pockets in the region between both side walls 33 of the pocket to a depth 37′. Collisions can be prevented in that recesses are provided in the side walls 33 of the pockets 31 and in the spring members 34 through which the suction members 24 can be guided.

The carton sleeves 10 are unfolded through the following steps: Firstly a carton sleeve 10 is pushed out of the feeding mechanism 13 through the opening 22 by the lug 20 of the finger 19. There a suction member 24 of the transfer unit 14 adheres to the carton sleeve 10 by suction and advances said sleeve along the circular track 25. After approx. a third rotation of the drum 23 (angle of rotation of φ=120°) the carton sleeve 10 approaches the conveyor belt 15 and the pocket 31 assigned thereto. The transfer unit 14 and the conveyor belt 15 are arranged relative to each other such that an edge 38 of the carton sleeve 10, lying in the direction of rotation as seen from the front, abuts the pocket 31 first. Technically speaking, a corner between the back wall 32 and one of the side walls 33 of the pocket 31 serves as a stop for the edge 38. As soon as the edge 38 of the carton sleeve 10 touches the pocket 31, forces (apart from centrifugal forces) are only introduced to the carton sleeve 10 in two places: firstly, in the region of the suction member 24, which channels the carton sleeve 10, and secondly, on the front edge 38 of the carton sleeve 10. Both these places are spaced at a distance 39 apart. A specific arrangement of the transfer unit 14 relative to the conveyor belt 15 and specific movement speeds and movement directions of transfer unit 14 and conveyor belt 15 achieves the result that the distance 39 is continuously reduced during the insertion of the carton sleeve 10 into the pocket 31. In this manner, two reciprocally aligned forces 40, 41 are introduced to the carton sleeve 10, which lead to the unfolding of the carton sleeve 10. The carton sleeves 10 are unfolded solely as a result of the effect of the suction members 24 and the pocket 31 on the carton sleeve 10; separate devices for unfolding are not, however, required.

Precise and sufficiently deep insertion of the carton sleeves 10 into the pockets 31 is required for the type of unfolding described. This happens successfully in spite of the single rotational movement of the drum 23 due primarily to the fact that the suction members 24 do not adhere to the carton sleeves 10 by suction centrally, but at a distance 42 from the centre thereof. This distance 42 corresponds more or less to the sum total of the travel 21 and the offset 28 and may, for example, be in the region of between 0 cm and 6 cm, and more particularly, between 1 cm and 3 cm. In relation to the width of the carton sleeves 10, the distance 42 to the centre may be in the region of between 10% and 40% of the width of the carton sleeves 10.

FIG. 3 shows a system 43 for filling cartons with foodstuffs known from the prior art (EP 0 112 605 A2). The individual stations of the system 43 are only shown schematically in FIG. 3 as FIG. 3 is only intended to serve as an illustration of a potential area of application for a device 12 according to the invention for unfolding carton sleeves 10. The carton sleeves 10 (not shown in FIG. 3) are unfolded by a station 44 and transferred to the pockets 31 on the conveyor belt 15. The station 44 can be replaced by the device 12 according to the invention. The system 43 comprises a first carousel 45 in which the gable panels 9 of the carton sleeves 10 are pre-folded. The carton sleeves 10 then pass through a station 46 in which the base panels 8 of the carton sleeves 10 are pre-folded. After pre-folding, the base panels 8 of the carton sleeves 10 are folded together and sealed at a station 47. The conveyor belt 15 is then guided around a second carousel 48 in which the carton sleeves 10 sealed on the bottom side are filled with foodstuffs. At a further station 49, the gable panels 9 of the carton sleeves 10 are folded together and sealed. The now filled and sealed carton sleeves 10 are then removed from the pockets 31 of the conveyor belt 15 at a further station 50 and discharged from the system 43.

LIST OF REFERENCE SIGNS

1 Blank

2 Folding line

3, 4 Side panels

5 Front panel

6 Rear panel

7 Sealing panel

8 Base panel

9 Gable panel

10 Carton sleeve

11 Longitudinal seam

12 Device for unfolding carton sleeves

13 Mechanism for providing carton sleeves

14 Transfer unit

15 Conveyor belt

16 Housing

17 Hopper

18 Central plane

19 Finger

20 Lug

21 Travel

22 Opening

23 Drum

24 Suction member

25 Circular track

26 Distance

27 Rotational axis

28 Offset

29 Plane

30 Tangential plane

31 Pocket

32 Back wall

33 Side wall

34 Spring member

35 End of spring member

36 Distance between pockets

37 Minimum distances

37′ Depth

38 Edge of carton sleeve

39 Distance

40, 41 Forces

42 Distance

43 System

44 Station (unfolding)

45 Carousel (pre-folding of gable panels)

46 Station (pre-folding base panels)

47 Station (base sealing)

48 Carousel (filling)

49 Station (gable sealing)

50 Station (discharging)

F Force

ω Angular velocity of the transfer unit

φ Angle of rotation of the transfer unit

v Speed of the conveyor belt

α Angle of inclination 

1. A device for unfolding packaging carton sleeves comprising: a mechanism for providing flat carton sleeves, a transfer unit, which can be rotated about a rotational axis and which has a plurality of suction members for adhering to the carton sleeves by suction, and for transferring the carton sleeves to a conveyor belt, wherein the suction members are at a distance from the rotational axis, wherein the conveyor belt comprises at least one pocket for receiving the carton sleeves, wherein the distance between the suction members and the rotational axis is constant and consequently the carton sleeves are channelled along a circular track, and wherein all of the suction members are arranged at the same distance from the rotational axis of the transfer unit.
 2. The device according to claim 1, wherein the conveyor belt runs in a straight line in the region of the device.
 3. The device according to claim 1, wherein the conveyor belt runs in a curved direction in the region of the device.
 4. The device according to claim 1, wherein the mechanism has at least one movably mounted finger with a lug for separating the flat carton sleeves.
 5. The device according to claim 1, wherein the mechanism has a hopper for channelling the carton sleeves, wherein a central plane of which has an offset in relation to the rotational axis of the transfer unit.
 6. (canceled)
 7. The device according to claim 1, wherein the suction members are inclined at an angle to a tangential plane touching the circular track.
 8. The device according to claim 1, wherein the pockets have two rigid side walls.
 9. The device according to claim 1, wherein the pockets have a rigid back wall.
 10. The device according to claim 8, wherein the side walls of the pockets protrude vertically from the back wall and/or the conveyor belt.
 11. The device according to claim 1, wherein the pockets have at least one spring member for clamping the carton sleeve into the pocket.
 12. The device according to claim 11, wherein an end of the spring member is configured as hook-shaped.
 13. The device according to claim 1, wherein a minimum distance between the circular track of the suction members and a back wall of the pocket is shorter than a length of the side walls of the pockets.
 14. A method for unfolding packaging carton sleeves comprising the following steps: a) provision of carton sleeves by a mechanism, b) adhesion to the carton sleeves by suction and advancement of said carton sleeves by a transfer unit rotating about a rotational axis having a plurality of suction members, and c) unfolding the carton sleeves by inserting said carton sleeves into a pocket attached to a conveyor belt, wherein the transfer unit channels the carton sleeves along a circular track at a constant distance between the suction members and the rotational axis wherein the carton sleeves are unfolded solely as a result of the effect of the suction members and the pocket on the carton sleeve.
 15. The method according to claim 14, wherein the transfer unit rotates at an angular velocity greater than zero.
 16. The method according to claim 14, wherein the transfer unit rotates at a constant angular velocity.
 17. The method according to claim 14, wherein the conveyor belt moves at a speed greater than zero.
 18. The method according to claim 14, wherein the conveyor belt moves at a constant speed.
 19. The method according to claim 14, wherein the carton sleeves are separated in the mechanism by a movably mounted finger, which has a travel in the range of between 1 cm and 4 cm.
 20. The method according to claim 14, wherein the suction members establish a negative pressure in an angular range of 350°<φ<10°.
 21. The method according to claim 14, wherein the suction members dissipate the negative pressure in an angular range of 125°<φ<145°.
 22. The method according to claim 14, wherein the suction members adhere to the carton sleeves by suction at a distance from the centre thereof, which is in the region of between 0 cm and 6 cm. 